Dear editor
Although we clearly outlined our answers in our previous letter,Citation1 we are pleased to clarify further any remaining open issues. There might be diverse views with regard to comparators of the wearable cardioverter defibrillator (WCD). We would like to refer the readers to our previous answer,Citation1 where we explained our rationale for choosing the implantable cardioverter defibrillator as one of the comparators. It was selected based on broad indications stated in the CE mark and after discussions with clinicians. Furthermore, in this case, a change of the comparator, ie, the implantable cardioverter defibrillator, would not have led to a different result or conclusion.
As mentioned earlier, observational studies cannot prove efficacy of a particular intervention and randomized controlled trials (RCTs), which aim to reduce bias, are needed. It is important to clarify that according to the EUnetHTA guideline, nonrandomized interventional studies or observational studies might be included only to provide additional information to an RCT on relative efficacy or effectiveness or – under specific conditions when an RCT in not feasible – when very large effects are likely, or for the sake of a temporary decision, ie, early in the life cycle of a new intervention.Citation2 The WCD falls under none of these conditions. A recently published RCT by Olgin et alCitation3 on the use of the WCD after myocardial infarction showed that conducting an RCT of the WCD was possible, and more importantly, it showed the need of evidence derived from controlled studies for the sake of establishing efficacy. Citing the authors of the RCT, the WCD “did not result in a significantly lower rate of arrhythmic death than medical therapy during the first 90 days” post myocardial infarction.Citation3 This RCT was also included in a recent health-technology assessment (HTA) that concluded that the efficacy of the WCD had not been established.Citation4 A similar conclusion was arrived at in another recently published systematic review with a meta-analysis including the RCT as well as retrospective studies of Epstein and Chung (both studiesCitation5,Citation6 were discussed in the previous letters), suggesting that “more RCTs are needed to justify the continued use of WCD in primary prevention”.Citation7 Certainly, RCTs are required, since real-world data can potentially be misleading in the evaluation of effectiveness.Citation8
We do acknowledge that some data from observational studies are available; however, these data cannot be considered of high quality, ie, as data that could have been included for the assessment of effectiveness in our EUnetHTA report, due to the reasons outlined in our previous answer. The EUnetHTA report was undertaken according to the quality standards established by EUnetHTA following relevant guidelines and using the HTA Core Model® for rapid relative effectiveness assessment.Citation9 The argument that the inclusion of retrospective studies might mislead the manufacturer to believe that RCTs are not necessary is of course only an additional reason we have excluded this type of study. Nonetheless, one of the responsibilities of EUnetHTA as a European network is to set standards. Retrospective studies comprising larger patient populations were excluded from the assessment of both effectiveness and safety on these outlined grounds of hierarchy of evidence.
We acknowledge your critique with regard to the focus group; however, we disagree with your conclusion. The aim of qualitative research is to explore views, to learn about possible variations in experience and the meaning of this experience, and to create hypotheses that can then be further pursued.Citation10 We involved patients in the HTA process in order to give patients a voice and to gather perspectives on areas of their cardiac disease and on the WCD therapy. We did not apply a sampling strategy nor did we aim to reach a point of saturation: the purpose was to collect views from patients, who were selected according to the PICO (population, intervention, comparator, and outcome) question. The patients’ input was then fed into the EUnetHTA report. It would be indeed valuable to receive health-related quality-of-life data from an actual WCD study, but these were unfortunately not available. Such data were, however, collected in the RCT by Olgin at al,Citation3 but had not yet been published. We have been informed by the authors that these data are currently being analyzed.
There is an agreement among experts that inclusion of patient perspectives can complement HTA processes valuably.Citation11,Citation12 Various HTA institutes around the world have systems for patient involvement, and several groups have been formed to further advance and promote patient involvement in HTA.Citation13–Citation15 Moreover, the European Commission foresees the involvement of patients in the HTA process in their legislative proposal on strengthening EU cooperation on HTA, which is currently being discussed.Citation16
We appreciate again the opportunity to clarify the open issues.
Disclosure
The authors report no conflicts of interest in this communication.
References
- SperzelJStaudacherIGoeingOCritical appraisal concerning “Wearable cardioverter defibrillators for the prevention of sudden cardiac arrest: a health technology assessment and patient focus group studyMed Devices (Auckl)20181120120429922100
- European Network for Health Technology Assessment (EUnetHTA)Guideline; Internal validity of non-randomised studies (NRS) on interventions72015 Available from: https://www.eunethta.eu/wp-content/uploads/2018/01/Internal-validity-of-non-randomised-studies-NRS-on-interventions_Guideline_Final-Jul-2015.pdfAccessed December 12, 2018
- OlginJEPletcherMJVittinghoffEWearable cardioverter–defibrillator after myocardial infarctionN Engl J Med2018379131205121530280654
- ChiarollaEOrsoMGoetzGStanakMWildCJeffersonTWearable cardioverter-defibrillator (WCD) therapy in primary and secondary prevention of sudden cardiac arrest in patients at risk Update2018AGENAS & LBI-HTA Available from: http://eprints.hta.lbg.ac.at/1186/Accessed January 15, 2019
- EpsteinAEAbrahamWTBiancoNRWearable cardioverter-defibrillator use in patients perceived to be at high risk early post-myocardial infarctionJ Am Coll Cardiol201362212000200723916930
- ChungMKSzymkiewiczSJShaoMAggregate national experience with the wearable cardioverter-defibrillator: event rates, compliance, and survivalJ Am Coll Cardiol201056319420320620738
- MarsiAAltibiAMErqouSWearable Cardioverter-Defibrillator Therapy for the Prevention of Sudden Cardiac Death: A Systematic Review and Meta-AnalysisJACC Clin Electrophysiol20195215216130784684
- GersteinHCMcMurrayJHolmanRRReal-world studies no substitute for RCTs in establishing efficacyLancet20193931016821021130663582
- European Network for Health Technology Assessment (EUnetHTA)HTA Core Model®2016 Available from: https://www.eunethta.eu/hta-core-model/Accessed December 12, 2018
- DurandMAChantlerTPrinciples of Social ResearchLondonOpen University Press2014
- FriedAWildCBeteiligung von BürgerInnen und PatientInnen in HTA Prozessen. Internationale Erfahrungen und Good Practice Beispiele [Participation of Citizens and Patients in HTA Processes. International Experience and Good Practice Examples]WienLudwig Boltzmann Institut für Health Technology Assessment2016
- FaceyKPloug HansenHSingleAPatient Involvement in Health Technology AssessmentSingaporeSpringer Nature Singapore2017
- Health Technology Assessment InternationalPatient and Citizen Involvement Available from: https://htai.org/interest-groups/pcig/Accessed December 12, 2018
- European Network for Health Technology Assessment (EUnetHTA)Patients2018 Available from: https://www.eunethta.eu/stakeholders/patients/Accessed December 12, 2018
- European Patients’ AcademyClosing Report of EUPATI 2012–2017 Available from: https://www.eupati.eu/closing-report-eupati-2012-2017/Accessed December 12, 2018
- European CommissionHealth Technology Assessment - Strengthening EU cooperation beyond2020 Available from: https://ec.europa.eu/health/technology_assessment/eu_cooperation_enAccessed December 12, 2018